Summer in Chicago can bring high temperatures and humidity. For those who work, exercise or play outside, these high temperatures can be exhausting and even dangerous. Julian Bailes, MD, Chairman of the Department of Neurosurgery and Co-Director of the NorthShore Neurological Institute, discusses what can happen when we overwork ourselves in the heat, what the signs are and how to treat it.

What is exertional heat stroke? Is it dangerous?

Exertional heat stroke (EHS) is a serious medical condition that happens when the body overheats and is unable to cool down. It is triggered by physical exertion, particularly in hot and humid conditions. When people ignore the warning signs of overheating their condition can turn into a life-threatening emergency – EHS – which can threaten organ function or life itself. EHS can cause long term damage to the brain, liver, kidneys and other organs.

Who is at risk?

Physically active people, specifically athletes, soldiers, firefighters, manual laborers, agriculture and factory workers – even people engaged in ‘everyday’ activities such as yard work or home maintenance.

Fatigue and exhaustion during exercise occur more rapidly as heat stress increases and are the most common causes of withdrawal from activity in hot conditions. Muscle cramps in the leg or abdomen are the first sign of heat stroke. Other symptoms include dizziness, headache, nausea, vomiting and fainting from exhaustion. An increased heart rate, heavy breathing and hot, dry or red skin are also signs of EHS.

How is it treated?

EHS requires immediate medical intervention. If you suspect someone may be experiencing exertional heat stroke, call 911 immediately, move them to a cooler area and remove as much clothing as possible. Focus on lowering the body temperature of the victim with external cooling by applying cool, wet cloths or ice packs to their skin. If possible, get them to drink water until medical personnel arrive.